Data Model in DBMS
Table of Content:
A database model or simply a data model is an abstract model that describes how the data are represented and used. A data model consists of a set of data structures and conceptual tools, which is used to describe the structure of a database. Depending on the concept used to model the structure of the database, data models are categorized into three types, namely -
- High-level or conceptual data models
- Representational or implementation data models
- Hierarchical data model
- Network data model
- Relational data model
- Object-based data model
- Low-level or physical data models.
Conceptual data model: A conceptual data model describes the information used by an organization in a way that is independent of any implementation-level issues and details. The main advantage of the conceptual data model is that it is independent of implementation details and, hence, can be understood even by the end users having non-technical background. The most popular conceptual data model is the entity-relationship model.
Representational data model: The representational or implementation data models hide some data storage details from the users; however, they can be implemented directly on a computer system.
Physical data model: The physical data model describes the data in terms of a collection of files, indices and other storage structures such as record formats, record ordering and access paths. This model specifies how the database will be executed in a particular DBMS software such as Oracle, Sybase, etc. by taking into account the facilities and constraints of a given database management system. It also describes how the data are stored on a disk and what access methods are available to it.